BleepingComputer.com: No Post, Oh Nos!

so, i got my computer all together, and after a slightly rocky start i finally got it up and running, or so i thought

first it wouldnt take all 4 dimms of ram that i had in there, so i increased the voltage hoping that there just wasnt enough current to the ram. this solved the problem for a few hours, now it wont post at all.

i sent the mobo back thinking that was the issue due to the ram not working and whatnot, but that doesnt seem to be the problem. any other ideas?

What's the make and model of the mobo? What chipset does it have? Have you tried loading it with only 2 slots of RAM installed? Have you checked the BIOS updates that are available to see if any of them may address this issue?

i have tried booting it with all dimm configurations i could think of to no avail

the motherboard is a gigabyte GA-M57SLI-S4 NF570, nforce 570 being the chipset used. i had sent the mobo back for an rma, and received a new one, so i have to conclude that it is not the motherboard unless someone can think of something i am missing. would damage to the processor cause a no post like this?

also, how would i go about flashing my bios if i cant get the computer to boot?

You can't flash if you can't boot.

Disconnect everything but the:
CPU and cooler
Power Supply
CD drive
1 stick of RAM
video card (if it's not onboard)
mouse and keyboard
monitor

See if you can boot with a bootable CD. If so, then it's one of the things that weren't connected that was causing the problem.
If you still can't boot, then it's one of the things that are still connected. You can try different RAM sticks in different slots, and other different components to rule out most of the stuff.